Excellent longitudinal data are available on the development of alcohol use and abuse across the college years but little is known about the behavioral risks (e.g. risky sex, aggression, academic failure) that have been associated with collegiate drinking. Using web-based surveys and daily monitoring, the proposed research will track the alcohol use and behavioral risks of 6,600 students during the transition from high school to college and in each semester oftheir college years. Laboratory assessments will also be used to assess potential differences in cognitive abilities, risk perceptions, and behavioral inhibition among a subset of the sample that change (increase or decrease) and those who do not change their alcohol use, behavioral risks, or both, over time. Simultaneous equations analyses, latent growth curve models, and hierarchical multiple regression will be used to test five models of the associations among trait, background, individual beliefs and motivations, environmental factors, alcohol use, and behavioral risks: (a) a fully mediated model in which trait and background factors are mediated by individual and environmental factors in predicting alcohol use and behavioral risks, (b) a multiple pathway model in which trait and background factors influence alcohol use and behavioral risks through either individual or environmental factors, (c) a general deviancy model in which trait and background characteristics are directly associated with individual and environmental factors, alcohol use, and behavioral risks, which are correlated with one another, (d) an alcohol main effects model in which alcohol use and other risk factors are directly associated with participation in behavioral risks and alcohol-related behavioral risks, and (e) a moderated effects model whereby traits, individual beliefs, and motivations moderate the effects of alcohol on behavioral risks and alcohol-related behavioral risks. Assumptions underlying all models are that (a) the transition from high-school to college will be characterized by decreased supervision and increased accessibility of alcohol, and Co) developmental processes contribute to changes in both individual and environmental factors across the college years. By following a large sample of young adults as they transition from high school to college and becomesocialized into the college environment, the proposed research will document the natural evolution of drinking and the behavioral risks that may be exacerbated by alcohol. Identification of factors that increase or decrease both alcohol use and behavioral risks during college will have significant implications for policy and prevention efforts on college campuses.